Kneading device



Der- 11, 192s.

E. DE THEY KNEADING DEVICE Filed on.l alf Patented Dec. 11, 1928.

PATENT OFFICE.

EMANUEL DE TREY, OF ZURICH, SWITZERLAND.

KNEADING DEVICE.

Application filed October 31, 1927, Serial No. 229,977, and in Switzerland March 1G, 1927.

The subject matter of the present invention is a device for treating a paste adapted for making castings fordental purposes so as to render it ready for use. The device coniprises a barrel or cylinder for receiving a paste cartridge. Inside the cylinder two pistons coaxially movable relatively to each other are arranged, one of which is perforated for permitting its utilization as a kneading piston whilst the other has no perfora-tions in order to be used as an expelling piston. Thereby the perforated piston may be fixed to a piston rod endwise displaceable in the cylinder, that piston rod being surrounded by a second tubular piston rod for the non-perforated piston and axially displaceable relatively tothe first piston rod.

Both piston rods may be provided at their free ends with rings adapted to be held by the fingers of the operator to facilitate the displacement of the pistons.

A constructional example of the subject matter of the present invention is illustrated on the accompanying drawing, in which:

Fig. l shows the non-filled device in an axial section,

Fig. 2 shows the filled device in an axial section,

Fig. 3 is a plan view on an enlarged scale of the perforated piston.

In the drawing 1 denotes a cylinder, preferably made of metal, and provided at its lower end with a screw cap 2 to permit a paste cartridge 3 to beA inserted into the cylinder from below. 4.- is a piston fixed to a iston rod 5 which is provided at its upper en with two rings 6 by means of which the piston can be easily moved-up and down. The piston 4 is provided with perforations 7 (Fig. 3) through which the mass of the paste cartridge is forced repeatedly when the piston is reciprocated, whereby the aste iskneaded, the cylinder is preferably eated exteriorly during said operation for instance in a watery bath. The paste is thereby rendered pliant and suitable for the preparation ofcastings for dental purposes for instance by means of the known tooth-spoon.l Above the piston 4 a second piston 8 is provided which has no perforations and is fixed to a tubular piston rod 9 whichloosely surrounds the piston rod 5, and is provided at its upper end with rings l0 facilitating the upward and downward movement of the-piston 8. After the mass has been rendered pliant by a repeated up and down movement of the piston 4 the screw cap 2 is removed and the piston 8 is forced in the downward direction whereby the piston 4 follows the movement of the piston 8 when the former is in its uppermost position and the treated mass is expelled from the cylinder.

I claim:` t

l. A device of the type described, comprising in combination, a barrel, two pistons coaxially arranged in said barrel, one of said pistons being solid and the other perforated, and means adapted to reciprocate either of said pistons and independently or simultaneously of the other.

2. A device of the type described, comprising in combination, a barrel, two pistons coaxlally arranged in said barrel, one of said pistons being solid and the other perforated,

a piston rod xed to said perforated piston, and a hollow piston rod surrounding the first mentioned piston rod and fixed to said solid iston.

3. device of the type described, comprising in combination, a barrel, two pistons coaxially arranged in said barrel, one of said pistons being perforated and the other nonperforated, a piston rod fixed to said perforated piston and a hollow piston rod surrounding the first mentioned piston i'od and fixed to Said non-perforated piston, and a screw cap for closing said barrel.

4. A device of the type described, comprising in combination` a barrel, two pistons coaxially arranged in said barrel, one of said pistons being perforated and the other nonperforated, a piston rod fixed to said perforated piston anda hollow piston rod surrounding the first mentioned piston rod and l yfixed to said non-perforated piston, and handles on said piston rods for operating said pistons.

In testimony whereof, I havesigned my name to this specification.

EMANUEL DE TREY'. 

